The present invention relates to an improved combination lock. Combination locks are convenient devices since they do not require the use of keys. They are widely used on brief cases, trunks, etc. In addition, combination locks also can be used to lock doors, drawers, or lockers. On occasion, these locks may be used outdoors or under harsh environmental conditions that, over an extended period of time, may cause the locks to no longer operate properly. As explained more fully below, the present invention provides for improved weather resistance.
In addition, the present invention provides for increased resistance to unauthorized opening of the lock. Typically, combination locks utilize a plurality of disc-like tumblers each having a radial slot in one particular position. To open a conventional combination lock, the tumblers are rotated by a dial on the face of the lock in a prescribed manner so that all of the slots are in alignment and the shackle can be opened. As explained in U.S. Pat. No. 4,111,014, efforts have been made in the past to increase the security of the lock by making the dial turn smoothly. These efforts to provide increased security, however, have contributed to the difficulty of correctly turning the dial to the prescribed combination. The face of a conventional dial often is marked with numerals so that the user can turn the dial to the proper position to unlock the lock. These markings usually are separated by very small distances. The result is that sometimes the user may not properly turn the dial to its correct location. For instance, the dial may not be completely turned to the correct position, or alternatively it may be turned too far. These errors may be attributed to the user not being able to tell when the dial has been turned to its proper position, or also may be caused by overly rapid turning of the dial so that it is stopped at an incorrect position. As explained below, the present invention provides for easier, more accurate rotation of the dial without sacrificing security of the lock.
The present invention also improves the security of the lock. In the past, skilled persons have attempted unauthorized opening of such locks by applying high impact forces to the shackle, dial, or body of the lock to force it open. The present invention increases resistance to these unauthorized attacks in a number of ways, each of which is described more fully below.
Finally, conventional locks usually are mass produced in a manner that do not allow for customization to receive a logo or other design, or to suit a purchaser or particular customer segment without either incorporating these steps in the manufacture of the lock or exposing the lock to harmful elements. The present invention allows for customization of the lock after it has been assembled and without reducing the weather resistance or integrity of the lock.
The present invention is directed to an improved combination lock.
In one embodiment, the lock has a combination assembly made of rotatable disks. The disks have clearance pockets that, when aligned, allow a pushbutton to be depressed in order to open the lock. The pushbutton and disks are configured so that as the button returns to its original position the disks are rotated out of alignment, thereby requiring the combination to be reentered in order to reopen the lock.
In another embodiment, the combination dial and pushbutton of the lock are positioned so that the pushbutton operates in a direction perpendicular to the rotational axis of the dial. Preferably, the dial is located on the bottom face of the lock housing. Another embodiment of the present invention includes a collapsible cover over the pushbutton. The cover is designed to collapse under impact force to provide increased security against unauthorized attempts to open the lock by force.
In yet another embodiment, the combination lock has improved weather resistance. In this embodiment, the lock has a flexible insert with through holes for receiving the shackle. In one embodiment, the through holes have a diameter slightly less than the diameter of the legs of the shackle. The material around the through holes stretches to accommodate the shackle, thereby creating a seal that provides greater resistance to water, dust, or other impurities that may harm the lock. In another embodiment, the through holes have a diameter approximately the same as the shackle, or alternatively may be slightly larger than the shackle. In these embodiments, the edge of the through holes may have ribs that contact the shackle to provide increased weather resistance while resulting in less frictional force when the shackle is moved in or out of the lock.